Background and aimsArterial stiffness seems to be influenced by the dialysis method, but studies are sparse and the results discordant. High substitution volume online hemodiafiltration appears to have beneficial cardiovascular effects in dialysis patients, but its effects on arterial stiffness are not investigated. We aimed to analyze arterial stiffness parameters in high substitution volume post-dilution online hemodiafiltration and compare results to high-flux hemodialysis.MethodsWe studied arterial stiffness parameters using the oscillometric method (Arteriograph IrDA, TensioMed, Budapest, Hungary) in 23 non-diabetic patients on high substitution volume online postdilution hemodiafiltration and 23 non-diabetic patients on high-flux hemodialysis. Dialysis vintage was at least 6 months in all subjects.ResultsHemodiafiltration-treated patients showed a more favorable arterial stiffness profile. Pulse wave velocity was significantly higher in hemodialysis compared to hemodiafiltration patients (10.39±2.29 m/s vs 9.0±1.7 m/s, p=0.026). Augmentation indexes and the diastolic reflection area were also significantly elevated hemodialysis patients compared to hemodiafiltration patients.ConclusionsHigh substitution volume online postdilution hemodiafiltration could have a beneficial effect on arterial stiffness and should be assessed in properly sized controlled trials.

Aberrant DNA methylation is an emerging characteristic of chronic kidney disease including dialysis patients. It appears to be associated to inflammation. We compared the global DNA methylation status in 10 control subjects compared to 80 dialysis patients (N = 40 on-line hemodiafiltration, N = 40 high-flux hemodialysis) in relation to the dialysis technique and inflammation. Whole blood DNA methylation was assessed with a 5-mc DNA enzyme linked immunosorbent assay Kit. Global DNA methylation was higher in hemodialysis (HD) compared to on-line hemodiafiltration (HDF) patients (0.045 vs. 0.039; P < 0.0001) and controls (0.045 vs. 0.0284; P = 0.0002 for HD; 0.039 vs. 0.0284; P = 0.0254 for on-line HDF). To study the influence of the dialysis technique on DNA methylation we divided dialysis patients according to the median value of 5-mC. DNA methylation was highest in inflamed patients on hemodialysis. The dialysis technique was the only independent predictor of global DNA methylation in dialysis patients. On-line HDF could be associated with a favorable DNA methylation profile.